94420 + Interview Questions in Chemistry in Class 12

1.	In the nuclear reaction ""_(3) Li^(7) + ""_(1) H^(1) to 2""_(2) He^(4) . The mass loss is nearly 0.02 amu . Hence the energy released in the process is x xx 10^(2) million kcal l mole . (nearly) . Then 'x' is ____
Answer» SOLUTION :`Q = ((0.02 xx 931.5 xx 10^(6) xx 1 .602 xx 10^(-19) xx 6 xx 10^(23))/(4 .18 xx 1000)) = 42.84 xx 10^(3+ 4)` `= 4.284 xx 10^(8)` Kcal/mole = `4.28 xx (10^(8))/(10^(6))` million Kcal/mole = `4 xx 10^(2)` million Kcal/mole

Discussion

2.	In the nuclear reaction ._(12)Mg^(24) + ._(2)He^(4) = ._(0)n^(1) + ? The product nucleus is
Answer» `._(13)Al^(27)` `._(14)Si^(27)` `._(13)Al^(28)` `._(12)Mg^(25)` Solution :`._(12)Mg^(24) + ._(2)He^(4) rarr ._(0)N^(1) + ._(14)Si^(27)`

Discussion

3.	In the nuclear reaction ""_(42)^(96)Mo +"".......to""_(43)^(97)Tc+""_(0)^(1)n the missing particle is :
Answer» DEUTRON PROTON `ALPHA`-particle tritium. Answer :A

Discussion

4.	In the nuclear reaction : ""_(13)^(27)Al+""_(2)^(4)Heto""_(15)^(30)X+""_(0)^(1)n the element X is :
Answer» S C P Si Answer :C

Discussion

5.	In the nitration of phenol with a mixture of conc. HNO_3 and conc. H_2SO_4, the active species involved is
Answer» NITRITE ion nitronium ion nitrate ion nitrogen peroxide Answer :B

Discussion

6.	In the nitration of benzene with a mixture of conc. HNO_3 and conc. H_2SO_4, the active species involved is:
Answer» NITRITE ion Nitrate ion Nitronium ion Nitrogen dioxide Answer :C

Discussion

7.	In the nitration of benzene using a mixture of conc. H_(2)SO_(4) and conc. HNO_(3), the species which intiates the reaction is______
Answer» `NO_(2)` `NO^(+)` `NO_(2)^(+)` `NO_(2)^(-)` ANSWER :C

Discussion

8.	In Nitrogen family the H-M-H angle in the hydrides MH_(3) gradually becomes closer to 90^(@) on going from N to Sb. This due to
Answer» The basic STRENGTH of hydrides increases Almost pure p-orbitals are used for M-H BONDING The bond energies of M-H bond increases The bond pairs of electrons becomes NEARER to the central ATOM ANSWER :D

Discussion

9.	In the nitration of benzene using a moisture of Conc H_(2)SO_(4) and conc. HNO_(3) the species which initates the reaction is:
Answer» `NO_(2)` `NO^(+)` `NO^(+)_(2)` `NO^(-)_(2)` ANSWER :C

Discussion

10.	In the nitration of benzene using a mixture of conc. H(2)SO_(4), the species which initiates the reaction is :
Answer» `NO_(2)` `NO^(+)` `NO_(2)^(+)` `NO_(2)^(-)` ANSWER :C

Discussion

11.	In the nitration of benzene using a mixture of conc. H_2 SO_4 and conc. HNO_3, the species which initiates the reaction is
Answer» `NO_2` `NO^(+)` `NO_(2)^(+)` `NO_(2)^(-)` SOLUTION :NITRATION of benzene is an ELECTROPHILIC substitution reaction. The electrophile which attacks the benzene ring in this reaction is nitronium ion `(NO_(2)^(+)`).

Discussion

12.	In the nitration of benzene using a mixture of conc. H_2SO_4 and conc. HNO_3, the species which initiates the reaction is _______________ .
Answer» `NO_2` `NO^(+)` `NO_(2)^(+)` `NO_(2)^(-)` SOLUTION :Nitration of benzene is an electrophilic SUBSTITUTION reaction. The electrophile which attacks the benzene ring in this reaction is NITRONIUM ion `(NO_(2)^(+)`).

Discussion

13.	In the nitration of aniline the amino group is protected by conversion into
Answer» TRIBROMO derivative Isocyanide Diazonium salt Acetyl derivative Answer :D

Discussion

14.	In the nitration of benzene, the electrophile is _____.
Answer» ANSWER :`NO_2^+`

Discussion

15.	In the neutralisation between sulphuric acid and potash, identify spectator ions.
Answer» Solution :The molecular equation is `H_(2)SO_(4) + 2KOH rarr K_(2)SO_(4) + 2H_(2)O` The ionic equation is `2H^(+) + SO_(4)^(2-) + 2OH^(-) rarr 2K^(+) + 2SO_(4)^(2-) + 2H_(2)O` The SPECTATOR ions in the GIVEN reaction are `SO_(4)^(2-)` and `K^(+)`.

Discussion

16.	In the netallurgy of iron , when limestone is added to the blast furnace , the calcium ion ends up as :
Answer» Slag Gangue Metallic calcium Calcium carbonate Answer :A

Discussion

17.	In the Nernst equation, we substitute (2.303RT)/F=0.0591 where,
Answer» R = 8.314 J, T = 273 K and F = 96500 C R = 0.0821 L. atm, T = 298 K and F = 96500 C R = 8.314 J, T = 298 K and F = 96500 C R = 2.0 CAL, T = 298 K and F = 1 C Answer :C

Discussion

18.	In the natural rubber ' Caoutchouc'. The isoprene units are joined by
Answer» HEAD-to -head Tail-to-tail Head-to-tail All of these Solution :`overset("Head")(CH_(2))=underset(CH_(3))underset(\|)(C)-CH=overset("Tail")(CH_(2))+ overset("Head")(CH_(2))=C-underset(CH_(3))underset(\|)(C)H=overset("Tail")(CH_(2)) to (-CH_(2)-underset(CH_(3))underset(\|)(C)=CH-CH_(2)-CH_(2)-underset(CH_(3))underset(\|)(C)=CH-CH_(2)-)_(n)` From steric effects, the polymer formed has head to tail CONFIGURATION.

Discussion

19.	In the NaCl crystal, which of the following facts is not true?
Answer» `NA^(+)` IONS form f.C.c lattice `Cl^(-)` ions form f.c.c lattice `Na^(+)Cl^(-)` UNITS from f.c.c STRUCTURE CN of each `Na^(+)` and `Cl^(-)` is 6 Answer :C

Discussion

20.	In the mood'sprocess, ........is usedto purify impure nickel.
Answer» ANSWER :CO

Discussion

21.	In the NaCl crystal, the coordination number of each ion is 6. How can the CN change to 8?
Answer» By INCREASING temperature By KEEPING it for some time By increasing pressure CN does not CHANGE by any way Answer :C

Discussion

22.	In the monochlorination of 3-methylpentan, let x be the number of pairs of isomers which exist as enantiomers, y be the number of pairs of isomers which exist as diastereomers, z be the number of isomers which are achiral. Calculate the value of x+y+z.
Answer» Solution :`CL-C-C-underset(*)overset(C) overset(\|)(C)-C-Cto` one CHIRAL CARBON pair of enantiomers. `C-C-overset("CC"L) overset(\|)(C)-C-Cto` achiral MOLECULE `C-C-underset(Cl)underset(\|) overset(C) overset(\|) (C)-C-Cto` achiral molecule `x=3, y=4, z=2` `x+y+z=9`

Discussion

23.	In the mond process,impure nickel is heated with …………..compound.
Answer» SOLUTION :CARBON MONOXIDE

Discussion

24.	In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending uponthe type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s,p,d, and f. the modern periodic table consists of 7 periods and 18 groups. each period begins with the filling of a new energy shell. in accordance with the aufbau principle, the seven periods (1 to 7) have 2,8,8,18,18,32 and 32 elements respectively. the seventh period is still incomplete. to avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the maini body of the periodic table. Q. The element with atomic number 57 belongs to:
Answer» s-block p-block d-block f-block Solution :`[XE]^(54)6S^(2)5D^(1)` (last `e^(-)` INTERS to d-orbitals)

Discussion

25.	In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending uponthe type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s,p,d, and f. the modern periodic table consists of 7 periods and 18 groups. each period begins with the filling of a new energy shell. in accordance with the aufbau principle, the seven periods (1 to 7) have 2,8,8,18,18,32 and 32 elements respectively. the seventh period is still incomplete. to avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the maini body of the periodic table. Q. Which of the elements whose atomic numbers are given are given below, cannot be accomodated in the present set up of the long form of the periodic table?
Answer» 107 118 126 102 Solution :In PRESENT set up of long form of PERIODIC table element with ATOMIC number>118 can not be accomodated.

Discussion

26.	In the modern blast furnances, the charge consists of a mixtureof
Answer» iron pyrites + BITUMINOUS coal hydrated iron oxides + dolomite + coke CALCINED iron oxide + limstone + coke calcined iron oxide + LIME + anthracite coal Solution :Iron pyrites and bituminous coal are charged in the modern blast furnance.

Discussion

27.	In the middle part of blast furnace, iron ore is treated with lime stone to remove
Answer» `C` `CAO` `SiO_2` `Fe_2 O` ANSWER :C

Discussion

28.	In the microcosmic bead test test Cu^(2+) imparts which colour to the flame
Answer» green yellow blue violet. Solution :`CuNaPO_(4)^(-)` the MICROCOSMIC BEAD formed is blue in COLOUR.

Discussion

29.	In the middle part of blast fumace, irone is treated with limestone to remove
Answer» C CaO `SiO_(2)` `Fe_(2)O` ANSWER :C

Discussion

30.	In the Mg-Al cell, the number of electrons involved in the cell reaction is.
Answer» SOLUTION :The CELL REACTION is `3Mg+2AL^(3+)to3Mg^(2+)+2Al,n=6`

Discussion

31.	In the metallurgy of zinc, the zinc dust obtained from roasting and reduction of zinc sulphide contains some ZnO. How is this removed
Answer» ABSORBANCE of ultraviolet LIGHT and re-emission of white light is employed Shock cooling by CONTACT with a shower of molten lead is done X-ray METHOD is used Smelting is empolyed Answer :D

Discussion

32.	In the metallurgy of Zinc, the Zine dust obtained from roasting and reduction of ZnS contains same It is removed by
Answer» Absorbance of UV light and reemission of white light Shock COOLING by contact with a shower of molten lead X-ray method smelting Solution :In the METALLURGY of Zinc, the Zinc DUST obtained from roasting and reduction of ZNS contains some ZnO. It is removed by shock cooling by contact with a shower of molten lead.

Discussion

33.	In the metallurgy of zinc , the zinc dust obtained from roasting and reduction of zinc sulphide contained some ZnO. It is removed by :
Answer» Absorbance of ultraviolet LIGHT and remission of white light Shock COOLING by contact with a shower of MOLTEN lead X-ray METHOD Smelting Answer :B

Discussion

34.	In the metallurgy of zinc, flux is not used because
Answer» ZINC ore has no impurities Zinc is VOLATILE hence easily SEPARATED Zinc REACTSWITH flux Flux is volatile Answer :B

Discussion

35.	In themetallurgyof whichof the followingsupellationprocessis used?
Answer» COPPER silver Iron Aluminium Answer :B

Discussion

36.	In the metallurgy of iron , when limstone is added to the blast furnace , the calcium ions are removed as :
Answer» Slag Gangue Metallic CA `CaCO_3` ANSWER :A

Discussion

37.	In the metallurgy of iron, when lime stone is added to blast furnace, calcium end up in :
Answer» Slag Gangue Metallic calcium Calcium carbonate. Solution :Lime stone `(CaCO_(3))` gives CaO upon HEATING. It acts as a basic fluxand COMBINES with the impurity of sand `(SiO_(2))` to form `CaSiO_(3)` (slag) in the BLAST furnace.

Discussion

38.	In the metallurgy of iron , when lime stone is added to the blast furnace , the calcium ion ends up in
Answer» GANGUE METALLIC CALCIUM Calcium CARBONATE Slag ANSWER :D

Discussion

39.	In the metallurgy of iron, the upper layer obtained in the bottom of blast furnace mainly contains:
Answer» SLAG PIG IRON Cast iron WROUGHT iron Answer :B

Discussion

40.	In the metallurgy of iron, limestone is added to coke. Which acts as a ______
Answer» REDUCING agent Oxidising agent Slag Flux Answer :D

Discussion

41.	In the metallurgy of copper ,the material obtained from the bottom of blast furnace is
Answer» COPPER MATTE SLAG CUPROUS oxide Solution :EXTRACTION of copper

Discussion

42.	Inthemetallurgyof copper, the fluxused to removethe basicimpurity ofFeOis ……….. .
Answer» ANSWER :`SIO _2

Discussion

43.	In the metallurgy of copper, matte is molten mass of
Answer» Cu and FeS CUO and Fe `Cu_(2)S and FeS` `Cu_(2)O and FEO` Solution :EXTRACTION of COPPER

Discussion

44.	In the extraction of copper, the metal formed in the Bessemer converter is due to the reaction
Answer» `CUS+O_2rarrCu+SO_2` `Cu_2S+O_2rarr2Cu+SO_2` `2Cu_2S+3O_2rarr2Cu_2O+2SO_2` `Cu_2S+2Cu-2Orarr6Cu+SO_2` `2CuS+3O_2rarr2CuO+2SO_2` `2CuO +CuS RARR 3Cu +SO_2` ANSWER :C

Discussion

45.	In the metallurgy of copper, blister copper is obtained from
Answer» BESSEMER converteer Reverberatory furnace Blast furnace Electrolytic tank Answer :1

Discussion

46.	In the metallurgy of copper blister copper is obtained from
Answer» BLAST furnace Reverberatory furnace Bessemer converter Electrolytic tank Answer :C

Discussion

47.	In the metallurgy of aluminium , cryolite is mixed in the molten state because it
Answer» Increases the MP of ALUMINA Oxidises alumina Reduces alumina Decreases the mp of alumina Solution :Cryolite `Na_(3)AlF_(6)` (1) Decreases the melting point of alumina (2) Increases CONDUCTIVITY of the solution

Discussion

48.	In the metallurgy of aluminium when the fused matrix is electrolyzed , the overall reduction reaction is :
Answer» `Al_2O_3 +3C RARR 2Al+3CO` `Al_2O_3 rarr2Al^(3+)+3O_2` `2Al_2O_3+3Crarr3Al+3CO_2` `Al_2O_3+2COrarr 2Al+2CO_2` ANSWER :C

Discussion

49.	In the matallurgy of aluminium………..
Answer» `Al^(3+)` is oxidised to Al (s). Graphite anode is oxidised to carbon monoxide and carbon dioxide. Oxidation state of oxygen changes in the REACTION at anode. Oxidation state of oxygen changes in the OVERALL reaction INVOLVED in the process. Answer :B

Discussion

50.	Inthemetallurgyofaluminium ........ .
Answer» ` Al^(3+) `isoxidised toAl (s) graphieanodeisoxidisedto carbonmonoxideandcarbondioxide oxidationstate ofoxygenchangesin thereactionatanode oxidationstate ofoxygenchanges intheoverallreactioninvolved in theprocess. Solution :Pleasenotethatoxidationstate ofO doesnotchangein either thereactionoccuringatthe anodeortheoverallreactionasshownbelow: Anode:`C +OVERSET ( 2-) Otooverset ( 2+) C +overset ( 2- ) O+2 e^- ,C +2 overset ( 2- )Otooverset ( 4 + ) C overset (2 - )(( O ) )_2` Overall REACTION :` "" overset ( +3 )(Al_2) overset (-2)O_3+3C to2 Al++3overset ( +2 )C overset (2 - ) O `. THUS,option(b) ISCORRECT.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

In the nuclear reaction ""_(3) Li^(7) + ""_(1) H^(1) to 2""_(2) He^(4) . The mass loss is nearly 0.02 amu . Hence the energy released in the process is x xx 10^(2) million kcal l mole . (nearly) . Then 'x' is ____

In the nuclear reaction ._(12)Mg^(24) + ._(2)He^(4) = ._(0)n^(1) + ? The product nucleus is

In the nuclear reaction ""_(42)^(96)Mo +"".......to""_(43)^(97)Tc+""_(0)^(1)n the missing particle is :

In the nuclear reaction : ""_(13)^(27)Al+""_(2)^(4)Heto""_(15)^(30)X+""_(0)^(1)n the element X is :

In the nitration of phenol with a mixture of conc. HNO_3 and conc. H_2SO_4, the active species involved is

In the nitration of benzene with a mixture of conc. HNO_3 and conc. H_2SO_4, the active species involved is:

In the nitration of benzene using a mixture of conc. H_(2)SO_(4) and conc. HNO_(3), the species which intiates the reaction is______

In Nitrogen family the H-M-H angle in the hydrides MH_(3) gradually becomes closer to 90^(@) on going from N to Sb. This due to

In the nitration of benzene using a moisture of Conc H_(2)SO_(4) and conc. HNO_(3) the species which initates the reaction is:

In the nitration of benzene using a mixture of conc. H(2)SO_(4), the species which initiates the reaction is :

In the nitration of benzene using a mixture of conc. H_2 SO_4 and conc. HNO_3, the species which initiates the reaction is

In the nitration of benzene using a mixture of conc. H_2SO_4 and conc. HNO_3, the species which initiates the reaction is _______________ .

In the nitration of aniline the amino group is protected by conversion into

In the nitration of benzene, the electrophile is _____.

In the neutralisation between sulphuric acid and potash, identify spectator ions.

In the netallurgy of iron , when limestone is added to the blast furnace , the calcium ion ends up as :

In the Nernst equation, we substitute (2.303RT)/F=0.0591 where,

In the natural rubber ' Caoutchouc'. The isoprene units are joined by

In the NaCl crystal, which of the following facts is not true?

In the mood'sprocess, ........is usedto purify impure nickel.

In the NaCl crystal, the coordination number of each ion is 6. How can the CN change to 8?

In the monochlorination of 3-methylpentan, let x be the number of pairs of isomers which exist as enantiomers, y be the number of pairs of isomers which exist as diastereomers, z be the number of isomers which are achiral. Calculate the value of x+y+z.

In the mond process,impure nickel is heated with …………..compound.

In the modern blast furnances, the charge consists of a mixtureof

In the middle part of blast furnace, iron ore is treated with lime stone to remove

In the microcosmic bead test test Cu^(2+) imparts which colour to the flame

In the middle part of blast fumace, irone is treated with limestone to remove

In the Mg-Al cell, the number of electrons involved in the cell reaction is.

In the metallurgy of zinc, the zinc dust obtained from roasting and reduction of zinc sulphide contains some ZnO. How is this removed

In the metallurgy of Zinc, the Zine dust obtained from roasting and reduction of ZnS contains same It is removed by

In the metallurgy of zinc , the zinc dust obtained from roasting and reduction of zinc sulphide contained some ZnO. It is removed by :

In the metallurgy of zinc, flux is not used because

In themetallurgyof whichof the followingsupellationprocessis used?

In the metallurgy of iron , when limstone is added to the blast furnace , the calcium ions are removed as :

In the metallurgy of iron, when lime stone is added to blast furnace, calcium end up in :

In the metallurgy of iron , when lime stone is added to the blast furnace , the calcium ion ends up in

In the metallurgy of iron, the upper layer obtained in the bottom of blast furnace mainly contains:

In the metallurgy of iron, limestone is added to coke. Which acts as a ______

In the metallurgy of copper ,the material obtained from the bottom of blast furnace is

Inthemetallurgyof copper, the fluxused to removethe basicimpurity ofFeOis ……….. .

In the metallurgy of copper, matte is molten mass of

In the extraction of copper, the metal formed in the Bessemer converter is due to the reaction

In the metallurgy of copper, blister copper is obtained from

In the metallurgy of copper blister copper is obtained from

In the metallurgy of aluminium , cryolite is mixed in the molten state because it

In the metallurgy of aluminium when the fused matrix is electrolyzed , the overall reduction reaction is :

In the matallurgy of aluminium………..

Inthemetallurgyofaluminium ........ .